The discovery of a human gene mutation that decreases the risk of developing Type 2 diabetes by two-thirds may be the key to a promising new gene-based approach to treating or preventing diabetes.

Researchers at the Broad Institute and Massachusetts General Hospital led an international team of researchers in a study looking at the impact of a single gene mutation on diabetes risk. The team analyzed the genomes of 150,000 people in Sweden, Finland, and Iceland and found that those with the mutant gene SLC30A8 had a 65 percent lower risk of developing type 2 diabetes, regardless of age, weight, or other factors typically associated with diabetes.

It's the first time mutated genes have proven helpful in diabetes research, says Louis Philipson, director of the University of Chicago's Kovler Diabetes Center. "For drug development, this is very powerful." Philipson was not involved in the study.

Type 2 diabetes results when the body can no longer produce enough insulin on its own, but those with the mutation seemed resistant to developing diabetes. Test subjects were fat and skinny, young and old, healthy and sick, exercisers and couch potatoes. Many drank and smoked. Oddly, none of that mattered in the folks with the mutation.

All that did matter was that those with the rare SLC30A8 mutation were less likely to develop the disease. The exact way the altered gene exerts this effect is unclear.

Many scientists doubted the study could be valid, since the same mutation in mice lab tests led to the opposite result – mice made less insulin and were more likely to develop diabetes. This mystery is yet to be solved. But researchers say human findings warrant more study that could lead to a drug to prevent Type 2 diabetes in a wide range of adults. It could be 10 or more years away, they caution.

The project was published in the March 2014 issue of "Nature Genetics." Drug firms Pfizer and Amgen and several universities cooperated. The National Institutes of Health funded one academic study.